In the petroleum refining industry a need has arisen for a prefabricated laboratory housing an octane analyser unit and which can be transported to and placed on site with the minimum of site preparation. This is particularly so in the case of in-line gasoline blending operations where continuous monitoring of the octane rating of the gasoline being blended is necessary so that rapid adjustments can be made in the feed rates of the various components should the obtained octane number fluctuate from the desired value. Customarily octane ratings are monitored using a standard engine which is fed alternately with a reference fuel of known octane rating and the line gasoline. The knock intensities of the two fuels are evaluated and compared electronically in a comparator and a control signal produced proportional to the variation of the octane rating of the line gasoline from the desired value. This control signal is then used to adjust the flow rate of, for example, the lead alkyl antiknock compound so as to adjust the octane value of the line gasoline to the desired value. To save labour and other costs it is desirable that the analyser be provided as a prefabricated unit which can be transported to and installed on site ready to operate with the minimum of site preparation. However, a prime requirement for the reference engine is a substantially vibration-free mounting which requirement conflicts with the requirement for prefabrication and transportability.
Prefabricated portable buildings are, of course, well known, including prefabricated portable laboratories constructed to the internationally standard dimensions of a container according to the internationally agreed Container-Transport-System (CTS), see for example, German OLS 2 054 684 and 2 217 862, but, in general, such prefabricated laboratories do not recognise or solve the problem of providing a substantially vibration-free mounting for apparatus to be installed in the laboratory and which is sensitive to vibration and which therefore requires a vibration-free mounting.